Frank de Jonge has a new post to his site covering something that always seems to be a difficult topic in development: time. In his post he suggests that date and time handling in your application is a "dependency" that could be difficult test.

When developers talk about the infrastructural boundaries or external dependencies they often talk about databases and third-party integration. They're the first thing we'll put behind an interface so we can stub them out during our tests. This gives us some control over them. It's become relatively easy to spot these dependencies because we do it frequently. They're the usual suspects.

However, some "dependencies" are much harder to spot. They even live right inside the standard library of PHP and often manage to seep through the cracks. Date/Time handling is such a thing. So what's the problem and how do we fix it?

He goes on to talk about date/time handling programming languages in general and how its variance can can cause issues that might be out of our control. He suggests that when time "gets the best of you" you should opt to be more specific in your date/time handling (the cause is usually precision). He then gets into some code examples of how to "control time" by reducing the impact that direct date/time handling could have on your application. He also includes an example of testing this handling and finishes with the idea of "consuming time as a service".